Telephone equipment



P 7, 1964 H. E. MCALLISTER Re. 25,551

- TELEPHONE EQUIPMENT Original Filed Sept. 19', 1958 6 Sheets-Sheet 1omc. om. CLEAD IOOOW MAN. START CALL START HOLD 5: s2 s3 54 5s *h%r*=afi k? W o l2 3 III E I INVENTOR.

HARRY E. McALLlSTER FIG. 4 FIG. 5

FIG. 6 FIG. 7 r I W ATTORNEY April. 7, 1964 H. E. MQALLISTER TELEPHONEEQUIPMENT 6 Sheets-Sheet 2 Original Filed Sept. 19', 1953 mon 00. nth

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INVENTOR HARRY E. McALLISTER hum Tvm

. a, m .n m 5 ATTORNEY A ril 7, 1964 H. E. MQALLISTER TELEPHONEEQUIPMENT Original Filed Sept. 19, 1958 a Sheafis-Shet a HARRY a. MCALQSER ATTORN EY April 7, 1964 H. E. MCALLISTER 25551 TELEPHONE EQUIPMENTOriginal Filed Sept. 19, 1958 e Sheets-Sheet 4 HARRY E. MALLISTERATTORNEY A ril 7, 1964 H. E. MJALLISTER TELEPHONE EQUIPMENT OriginalFiled Sept. 19', 1958 6 Sheets-Sheet 5 INVENTOR. HARRY E. McALLlSTER NQQWON

ATTORNEY April 7, 1964 Original Filed Sept.

H. E. MCALLISTER TELEPHONE squxm a Sheets-Sheet s INVENTOR. HARRY E.McALLlSTER TTO BNEY United States Patent ()fitice Re. 25,551 ReissuedApr. 7, 1964 25,551 TELEPHONE EQUIPMENT Harry E. hIcAllister, 3201Bonnieview Drive, Lima, Ohio Original No. 3,069,512, dated Dec. 18,1962, Ser. No. 762,110, Sept. 19, 1958. Application for reissue Oct. 9,1963, Ser. No. 315,098

Claims. (Cl. 179175.2)

Matter enclosed in heavy brackets [J appears in the original patent butforms no part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

The invention disclosed and claimed in this application relates totelephone equipment. In illustrations of the invention I have disclosedan apparatus designed for the purpose of testing the operating telephonecircuits, switches and other equipment of a telephone system todetermine the efiiciency thereof and to locate faults therein.

OBJECTS One of the objects of my invention is to provide testingequipment operative to dial selected numbers automatically andcontinuously without supervision until a fault is encountered andthereupon to seize such faulty equipment and hold it until supervisingpersonnel can locate and correct such fault.

A further object of my invention is to provide a device which willoperate the dial central oflice equipment exactly as a subscriber on theexchange would operate the central office equipment in dialing for anynumber that he or she may wish to dial and that is served by the centralofiice equipment, operating the central oflice equipment under the sameconditions as encountered by a subscriber, that is, under both lightload or heavy load conditions.

A further object of my invention is to provide a device which will testthe complete train of the central oflice equipment at the same time,just as a subscriber would do in dialing a number.

A further object of my invention is to provide equipment to test dialtelephone central office equipment to determine the grade of service thesubscribers attached to the dial central ofiice equipment are receiving,and to provide information to show the type of service beingreceived-whether one call is lost in 500 attempts, 800 attempts, 1000attempts, or 2500 attempts, etc. It accomplishes this result bycontinuously dialing, automatically, predetermined or selected numberswithout close supervision. These numbers can be any numbers served bythe central ofiice equipment. The equipment records the number of callsattempted and the number of calls completed. To this end two registeringmeters are provided, one for registering the total number of callsoriginated and one for registering the total number of calls completed.These meters indicate the physical condition of dialing equipmentinasmuch as the number of lost calls can readily be obtained from acomparison of the two meters. Thus by subtracting the calls completedmeter reading from the calls originated meter reading, the grade ofservice being received by the subscribers can be accurately obtained.This information is very necessary from the standpoint of personnel atthe executive level.

A further object of my invention is to provide a device by which allelements of the switch train of a telephone central ofiice equipment aretested when connected in the normal manner. In larger ofiices, theelements concerned are staggering in number. If, for instance, you werein a large telephone exchange, say at telephone Catherine 5-6646 andcalling telephone No. Catherine 9-9616 the call would go through a linefinder, a first selector,

a second selector, a third selector, anda connector switc When thereceiver is first lifted to get a dial tone, the call can be picked upby any one of 20 line finder switches. Each of these line finderswitches has 50 first selector switches which actually furnish the dialtone. So at this point, a subscriber has had a possible choice of 20x50or 1000 possible paths to get the dial tone. The subscriber now dialsthe CA. This will give him a second selector switch, and since eachfirst selector switch has a choice of 20 second selector switches, wenow have had a possible choice of 20 times 1000, or 20,000 possiblepaths to reach a second selector switch. The subscriber now dials thefirst 9. This will get a third selector switch; and since each secondselector switch has a choice of 20 third selector switches, thesubscriber has had a possible choice of 20 times 20,000 or 400,000possible paths to reach a third selector switch. The subscriber nextdials the second 9. This will get a connector switch. Each thirdselector switch has a choice of 20 connector switches," so that now thesubscriber has had a choice of 20 times 400,000 or 8,000,000 possiblepaths to the connector switch. He now dials the 616 which is all dialedon the connector switch, and since the subscriber had a choice of 20connector switches, each one having a choice of the 616, he now has hada choice of 20 times 8,000,000, or 160,000,000 possible paths to reachthe number dialed.

011 the basis of the above, it is easily seen that the maintenancepersonnel has a very difficult task to try on a manual basis (i.e.without some device such as that which I have provided) to locate afault which may be encountered in such a dialing process. At the verybest, it is a time and energy consuming process. My automatic dialingroutiner eliminates this as it will dial and re-dial until it runs intothe fault, and then hold the equipment for the maintenance personnel tolocate and correct. It is very valuable in testing out new equipmentinstallations, prior to placing the new equipment into service.

Features of my invention include the following:

(1) It will test the local subscribers central office dial equipment.

(2) It will test the toll dial central oilice equipment.

(3) It can be attached to any local subscribers line equipment served bythe exchange.

(4) It can dial any local subscribers number served by the exchange.

(5) It can dial any toll code served by the exchange.

(6) It can be attached to any selector switch in the number or codetrain.

(7) When the number being dialed has been correctly reached, it willautomatically release the switch train and re-dial the number or code.This re-dialing or re-cycling will continue until a failure isencountered.

(8) If the correct number or code is not reached, it will stop dialing.

(9) When the dialing is stopped for any reason, an uninterrupted alarmis sounded.

(10) It registers the number of calls originated.

(11) It registers the number of calls completed.

(12) It will release the switch train and re-dial the number or codeupon the receipt of an A.C. generator current to the called number endof the routiner.

(13) It will release the switch train and re-dial the number or codeupon the receipt of a T-R lead reversal to the calling number side ofthe routiner.

(14) It will not start dialing until the equipment attached to thecalling number side of the routiner notifies the routiner it is ready toreceive the dialing pulses from the routiner.

(15) The dialing pulses are created by a three-relay free running pulsegenerator.

(16) A jack is provided to measure the correctness Q of the createdpulses by the use of an external pulse meter.

(17) A jack is provided to attach a receiver to the switch train tolisten for any busy or equipment butt-1n encountered.

(18) A lamp is provided to visually indicate that the pulse generator isrunning, giving a visible flashing lamp signal.

(19) A lamp is provided to visually indicate that the connector switchis prepared to be answered.

(20) It provides a hold ground to hold the switch train if a fault isencountered on the T-R loop during dialing.

(21) It may be released manually.

(22) An attendant, after placing the routiner in operation, is no longerrequired until a fault is encountered. This fault will be indicated bythe sounding of the uninterrupted alarm.

(23) While the embodiment illustrated shows a device which can dial anumber containing a total of ten digits, more switches can be added ifdesired so as to dial a total of more than ten digits. The equipment cantransmit 1 to 10 (or more) digits.

(24) The dialing can be limited to any number of switches up to thetotal provided by the device simply by setting a trunk off switch to thetotal number of digits contained in the number to be dialed. The numberof digits being dialed can be manually controlled, simply by setting thetrunk off switch on position #1 and then advancing it one step at a timeas each digit has been dialed, until the total digits desired has beendialed. This feature allows the maintenance personnel to examine eachindividual piece of equipment for proper functioning as it is beingdialed.

(25 Timing between digits is variable, being controlled by the settingof the 10,000 ohm variable resistor in series with the 500 mi.electrolytic condenser and relay D.

(26) Adequate contact spark protection is provided.

(27) The routiner may be used to dial from any part of the switch trainused in the calling number equipment, by attaching the tip-ring-s-leevewires of the cord used for the calling number equipment to thetip-ring-C leads respectively of the desired switch.

(28) The audible alarm will sound intermittently as long as the dialingis proceeding, thus giving maintenance personnel an audible indicationthat the dialing is procecding.

(29) No highly trained personnel are required to maintain the simplifiedapparatus and circuit.

(30) The apparatus creates and transmits pulses.

(31) The apparatus will not transmit pulses until the dial equipment isready to receive them, and for this it does not depend upon receipt ofthe dial tone.

(32) Manual pulsing can be used with a test telephone plugged into thereceiver jack, which operation is valuable for testing the differencesof operation of certain types of equipment.

(33) A test telephone can be plugged into the receiver jack and can beused to listen or talk, during or after the sending of one or moredigits, which is valuable for checking busys or butt-ins.

(34) When the equipment is dialing any number on the exchange, atelephone may be even left on the line and observed to determine whetherthe bells are ringing properly.

(35) The equipment will re-cycle upon the receipt of ringing currentalone from the connector switch, or wait until both ringing current andreversal of battery is received from the connector switch.

(36) The equipment tests the connector switch ringing feature.

(37) The equipment tests the connector switch answer feature the same asa subscriber would do on lifting the receiver after the bells have beenrung.

(38) The equipment tests the connector switch for reverse batteryfeature which is valuable for toll train equipment tests.

(39) The equipment gives a visible (steady lamp) indication that thereverse battery operation of the connector switch is to be used to causethe routiner to re-dial.

(40) The equipment wiil put positive battery forward on the C-lead tohold the switch train for certain types of encountered faults such asopen tip or ring leads.

(41) The equipment provides optional loop resistance for seizing thecentral oifice equipment.

Further objects and features of my invention should be apparent from thefollowing specification and claims when considered in connection withthe accompanying drawings illustrating embodiments of my invention.

DRAWINGS I have illustrated embodiments of my invention in theaccompanying drawings wherein:

PEG. 1 is a view in front elevation of routiner apparatus for testingtelephonic equipment comprising one embodiment of my invention;

FIG. 2 is a view in end elevation of the routiner apparatus shown inFIG. 1;

FIG. 3 is a diagrammatic sketch showing the relationship of FIGS. 4, 5,6 and 7 to each other, such FIGS. 4, 5, 6 and 7 consisting together of awiring diagram of the wiring, relays, switches, resistances, condensers,etc. contained within the casing of the routiner illustrate-d in FIGS. 1and 2;

'FIG. 4 is a diagrammatic drawing showing the upper left hand section ofthe wiring diagram referred to above in connection with FIG. 3;

FIG. 5 is a diagrammatic drawing showing the upper right hand section ofthe wiring diagram referred to above in connection with FIG. 3;

FIG. 6 is a diagrammatic drawing showing the lower left hand section ofthe wiring diagram referred to above in connection with FIG. 3;

FIG. 7 is a diagrammatic drawing showing the lower right section of thewiring diagram referred to above in connection with FIG. 3; and

FIG. 8 is a diagrammatic drawing showing a simplified wiring diagram ofa portion of the wiring, relays, digit switches and the steppingswitches, etc. of the illustrative embodiment of my invention, some ofthe switches and wiring being omitted for simplicity and some of theswitches being simplified for clarity.

DETAILED DESCRIPTION Referring specifically to FIGURES l and 2 of thedrawings, I have shown in FIG. 1 a front view of my dialing routiner. Asmay be seen, it comprises a casing 8 having a front panel 9. It has aside panel 10 and an upper face 11. It has a bottom face 12, rear face13 and second end face 14. The upper face 11 is provided with twohandles 15 and 16. On the front panel 9 there are provided digitswitches 17, 18, 19, 20, 21, 22, 23', 24, 25 and 26, and trunk offswitch 27. There are also provided a pulse generating starter toggleswitch 31, a toggle switch to originate calls 32, a dial start toggleswitch 33, a C-lead hold toggle switch 34, a thousand ohm loop toggleswitch 35, a manual release toggle switch 36, and an answer connectortoggle switch 37. Also provided on the face of the front panel 9 is apulse generator lamp 41 and an answer connector lamp 42. Also providedon the front panel are indicating meters for calls originated andcompleted. The indicating meter for the calls originating is designatedas 43, the indicating meter for calls completed is designated as 44. Onthe end panel 10 there is provided an alarm bell 45. Also, on the endpanel 10 there are provided five jacks. Thus there is provided a jack'51 for the calling number plug, a jack 52 for the pulse check plug, ajack 5 3 for the receiver plug, a jack 54 for the called number plug,and

a jack 55 for the battery plug. The jack '55 has a conhection 56 topositive ground and a connection 57 to negative battery (see FIG. 4).

The digit switches, toggle switches, tip ring and sleeve leads of theplug jacks, lamps, meters, are all interconnected by wiring as shown inFIGS. 4, 5, 6 and 7, the wiring of the four figures being interconnectedas diagrammatically indicated in FIG. 3.

PREPARATION FOR OPERATION When the routiner is initially prepared foroperation, all seven of the toggle switches 31-37, inclusive, are set totheir 011 positions. A battery plug is inserted in the battery groundjack 55 (FIG. 4) so that the tip wire of the plug is connected to anegative battery connection and the sleeve wire to positive batteryconnection or ground. This supplies operating current to the routiner.Next, a plug is inserted in the calling number jack 51 (FIG. 5). Thetip, ring and sleeve wires are connected to the line equipmentassociated with the number selected to be used as the calling number sothat the tip wire is connected to the tip of the line, ring wire to thering of the line, and the sleeve wire to the C-lead of the lineequipment. Next, a plug is inserted in the called number jack 54 (FIG.5) and the tip and sleeve wires are connected to the tip and ringrespectively of the line equipment associated with the number selectedto be used as the called number. Next, the digit switches 17 to 26,inclusive (FIGS. 6 and 7), are set to the various digits contained inthe called number (i.e. digit switch 17 is set to the first digit of thenumber, digit switch 18 to the second digit of the number, digit switch19 to the third digit of the number, etc.). Next the trunk off switch 27(FIG. 7) is set to the number corresponding to the total number ofdigits contained in the selected number to be dialed. Next, the pulsegenerating starter toggle switch 31 (FIG. 4) is moved to its onposition. This starts the three-relay (relays 61, 62 and 63- FIG. 4)pulse generator running.

PULSE GENERATOR The operation of this pulse generator is now explainedwith reference especially to FIG. 4 as follows: The spring 64 isconnected to ground and by means of the switch 31 is connected throughthe lead 65, lead 66, relay contacts 67, leads 68, 69 and 70 to therelay 61 and thence through lead 71 to negative battery connection at72. This energizes relay 61. Bypass 7374 connects the lead 70 throughresistance 75 with the lead 71. The relay 61 controls the relay contacts76 by which a lead 77 is connected to ground at 78. The lead 77 is alsoconnected to the relay 62 and through it to negative battery connectionat 79. Closing of contacts 76 by relay 61 energizes relay 62. A bypass76a is provided around relay contacts 76 with a rectifying unit 76binserted in the bypass to prevent arcing of the contacts 76. Such orsimilar rectifying units may be provided elsewhere in the variouscircuits to protect various contacts as desired.

The energizing of the relay 62 closes contacts 81 whereby groundconnection 82 is connected through leads 83, 84 and 85 to relay 63 andthrough it to negative battery connection 86. This energizes relay 63. Abypass connection 87 connects lead 83 with negative battery connection86, a resistance 88 being inserted in the bypass 87 in order to protectcontacts 81. It also increases the release time of the relay 63armature. Similar resistances may be provided elsewhere in the variouscircuits if desired for similar purposes. Pulse generating lamp 41 isconnected through a lead 89 with lead 84 whereby current can flow fromground 82 through switch 81, leads 83, 84 and 89, and pulse generatinglamp 41 to negative battery connection at 91. Therefore, as contact 81is closed by relay 62, relay 63 is energized and lamp 41 is caused to belit. The energizing of relay 63 breaks relay contacts 67 and closes arelay contact 92. It also closes relay contact 93 and opens relaycontact 94 (both shown in FIG. 6). The effect of the closing of contact92 and the closing of contact 93 and the breaking of contact 94 will bedisclosed hereafter.

The breaking of contact 67, however, breaks the connection between theground at 64 adjacent to the pulse generating starter switch 31 and thenegative battery connection 72 and thus de-energizes relay 61. This inturn breaks the contact connection at 76 and de-energizes relay 62 andthis in turn breaks the contact connection at 81 and de-energizes relay63 and causes lamp 41 to be extinguished. This in turn closes the relaycontact 67 and re-connects the ground 64 through the relay contact 67 toenergize relay 61 again as explained above. When ever contact 81 closes,the lamp 41 is lit and when contact 81 is opened, the lamp 41 isextinguished. The cycle is repeated again and again, the flashing of thepulse generator lamp 41 showing at each time of the energizing of relay63. The total time of each cycle bears a relation to the total time ofoperation of the three relays 61, 62 and 63. Increasing the number ofrelays or the time of operation of any one or more of them would changethe length of the pulsing cycle. This time cycle is efiectively used atcontact 92 to convey pulses to the calling number jack 51 and thecalling number equipment as will be later described.

OPERATION OF ORIGINATE CALLS SWITCH The next step in the operation ofthe routiner is to operate manually the switch to originate calls 32 toa closed position. This switch 32 is a double pole switch and iseifective (l) to complete a circuit to energize the relay and (2) tocomplete a circuit through the calling number equipment by means of thecalling number jack 51 and the line equipment associated therewith.

The toggle switch 32 has a ground at 102. The ground 162 of the doublepole switch 32 is connected through the subswitch 101 of switch 32 andthe lead 103, lead 164, relay contact 105, lead 106, lead 107, lead 108and lead 109 to the relay 100 and thus to the negative batteryconnection 111. The relay 100 is thus energized. Operation of the relay100 operates relay contacts 112, 113, 114, 115, 116, 117, 118 and 119(contacts 112, 113 and 114 are shown in FIG. 4 and all of the otherrelay contacts 115, 116, 117, 118 and 119 are shown in FIG. 6).

Relay 100 operates to close relay contacts 112, 114, 115, 117 and 119.It operates to break connections at contacts 113, 116 and 118. Thepurpose of the contacts 113, 114, 116, 117, 118 and 119 will bedescribed in detail later herein. The closing of the contact 112 iseffective as used in connection with the circuit established through thecalling number 51 and will be explained shortly. The closing of thecontact (FIG. 6) creates a circuit from the ground 120, through leads121 and 122 and through leads 84 and 85 (FIG. 4) through the relay 63 tothe negative battery connection 86. This energizes relay 63 irrespectiveof the condition of contact 81 and holds relay 63 energized so long asrelay 100 is energized and also maintains the circuit through the lamp41 closed so that the lamp continues shining and the pulsing generatorrelays 61 and 62 cease to operate. The purpose of the shorting of therelay 63 from the ground as just described is to insure the uniformityof the length of the first pulse when the pulsing is started for eachdigit as will be later more fully explained.

As stated above, a circuit is also completed by closing of toggle switch32 to the calling number telephone line and thus the calling number lineis seized. The tip wire of the line equipment of the calling number isconnected to positive or ground. The tip wire of the calling. numberplug is thus connected through the tip wire of the calling number toground and is in turn connected to the tip spring 123 (FIG. 5) of thecalling number jack 51. Spring 123 is connected through lead 124, lead125, tip spring 126 of receiver jack 53, lead 127, lead 128, lead 129(FIG. 4), resistance 131, lead 132, subsidiary switch 133 of toggleswitch 32, spring 134, lead 135, spring 136 (FIG. tip spring 137 of thepulse check jack 52, lead 138, lead 139 (FIG. 4), lead 141, relaycontact 112, lead 142, lead 143 (FIG. 5), and lead 144, upper coil l45of relay 146, lead 147, lead 148, lead 149, spring 151 ring spring 152of pulse check jack 52, lead 153, lead 154, relay contacts 155, lead156, lead 157, lead 1533, relay contacts 159, lead 161, lead 162, ringlead 163, and the ring spring 164 of the calling number jack 51 which 18connected to the ring of the line which is connected to the negativebattery. The line equipment has now been seized and, through itsoperation, a call has now been originated on the telephone equipmentwhich is now ready to receive pulses. Ground is now returned on thesleeve of the calling number plug from the telephone equipment.

It should be noted that the fact that although the relay 100 (FIG. 4) isenergizbed and its relay contact 112 is thereby closed, and the relaycontact 112 thus 18 a part of this circuit to the calling number,nevertheless the relay 63 is also energized and thereby relay contact 92is also closed and the contact 92 thus makes a second path from lead 139through lead 165, contact 92, lead 166, to lead 142 to complete saidsecond circuit to the calling number.

The closing of contact 119 (FIG. 6) creates a circuit from ground 16%through contact 119, lead 171, lead 172 (FIG. 7), lead 173 (FIG. 5),lead 174, lead 1'75, and lead 176 to alarm 45, and thence to negativebattery connection 177, thus causing the alarm to sound.

OPERATION OF RELAY 191 Thereafter the dial start toggle switch 33 (FIG.4) is manually operated to its closed position. This causes a circuit tobe formed from the ground of the sleeve of the calling number jack 51(FIG. 5) through the sleeve spring 181 of said calling number jack 51,thence through leads 182, 183, 134 (FIG. 4), switch 33, lead 185, lead1156, relay contact 187, lead 180, contact 189, lead 190, relay 191, andto the negative battery connection 192. This energizes relay 191. Theenergizing of relay 191 operates contacts 193, 194, 139, 195, 196, 197,198 and 199 (196, 197, 198 and 199 being shown in FIG. 6). Contacts 189,193, and 199 are broken by energization of the relay 191. Contacts areclosed in contacts 194, 195, 196, 197 and 198, by reason of theenergizing of the relay 19 1. The breaking of contacts 193 has no effecton the circuits (previously described) from the ground 102 through therelay 100 to the battery connection 111. However, it does insure that ifcontact 193 is opened by relay 191 at a time when contact 105 is broken,no current flows from the ground 102 through switch 101, lead 103,switch 193, lead 201, switch 202, leads 106, 107, 108 and 109, to relay100 so long as relay 191 remains energized.

The making of contact 194 which occurs before the breaking of contact189 provides an alternate path for the fiow of current from the lead 185through lead 203, contact 194 and lead 190 through relay 191. Thus,regardless of the breaking of the contact at contacts 187 and 189, relay191 remains energized.

The closing of contact 195 provides a circuit which energizes one of thecoils of the relay 204. A ground 205 (FIG. 7) (which is the main groundof the circuit illustrated) is connected through relay contact 206, to alead 207, through a lead 208, relay contact 209, a lead 211, a lead 212(FIG. 6), lead 213 (FIG. 4), contact 195, lead 214, leads 215 and 216through upper coil 217 of relay 204 and thence to negative batteryconnection 218. Relay 204 is thus energized.

The lead 212 (FIG. 4) is also connected to a lead 219 which is connectedby a normally open contact 221 to a lead 222 connected to the lower coil223 of the relay 204 and thence through the relay to a negative batteryconnection 224. When the upper coil 217 of the relay 204 is energized,it closes contact 221 so that the circuit is also formed through thelower coil 223 of the relay. Thus When the relay 204 is once energizedthrough the upper half 217 thereof, the contact 221 constitutes aholding circuit for the relay 204 and the relay 204 remains energizeduntil either the contact 206, or 209 is broken as will be laterdescribed.

The operation of relay 204 (FIG. 4) breaks the relay contact makescontact at the normally open relay contact 202; breaks the relay contact137; and closes the normally open relay contact 225; and as statedabove, closes the normally open relay contact 221. It also closes thenormally open relay contact 226 (FIG. 6). The effect of the opening ofrelay contacts 105 and 187, and the effect of closing the contacts 202,225 and 226, will be later described.

When the relay 191 (FIG. 4) is energized as stated above, it closesrelay contacts 196 and 197 (both shown in FIG. 6) which are in thecontrol circuits of minor switch magnets 231 (FIG. 6), and 232 (FIG. 7)controlling respectively the moving of wipers 251 and 252, (both in FIG.6), and of wipers 264 and 265 (both in FIG. 7). This operation will bedescribed more fully later.

The operation of relay 191 (FIG. 4), as explained above, also closesrelay contact 198 (FIG. 6) and thereby connects a ground 241 through therelay contact 198, the leads 242, 243 and 244 (FIG. 5) to the lower coil245 of relay 146 and thence to negative battery connection 246. Itshould be noted, however, that the current flowing through the lowercoil 245, of relay 146 flows in the opposite direction to the currentflowing through the upper coil of the relay 146 which is connected topositive battery at the tip spring 123 of calling number jack 51 and tonegative battery at the ring spring 164 of the calling number jack 51.The contacts controlled by the relay 146 are not opened or closed, asthe case may be, unless current is flowing through both parts of therelay in the same direction at the same time. Current flowing in eithercoil 145 or 245 alone is not strong enough to completely energize therelay 146. Therefore, current flowing through the lower part 245 ofrelay 146, as just described, has no effect on the contacts controlledby the relay 146.

OPERATION OF RELAY 204 Relay contacts 105 (FIG. 4) are broken by theoperation of relay 204 and thus (inasmuch as relay contact 193 hasnormally at such time been opened by relay 191) deenergizes relay 100.However, current now flows for a short time to charge the capacitor 248in series with the relay 100, and holds the relay 100 energized duringthis time, the time depending upon the adjustment of the variableresistor 249.

The relay contacts controlled by relay 204 (FIG. 4) (Le. contacts 105,202, 187, 225, 221 and 226, FIGS. 4 and 6) have the following effects,when 204 is energized: The breaking of the relay contact 105 breaks thecircuit from ground 102 to relay 100 and thus de-energizes relay 100 asjust stated above. The making of the contact at 202 has no effectbecause relay 191 has already broken the contact at 193 and the circuitfrom the ground 102 to the relay 100 thus remains incomplete. Thebreaking of the relay contact 187 has no effect because at such time thecircuit from to relay 191 (which previously passed through lead 186,contacts 187, lead 188, contact 189, lead 190, to the relay 191 andnegative battery connection 192) is now complete from lead 185 throughlead 203, relay contacts 194 (closed by the relay 191), lead 190, relay191 and negative battery connection 192. Contacts 194 are closed beforecontacts 189 are broken. The making of the connection at relay contacts225 is not effective because toggle switch 34 has not yet been turned tothe closed position. The making of the connection at contact 221provides a holding circuit for the relay 204 as previously describedfrom the main ground 205 through the leads 212 and 219, contacts 221,lead 222, and the lower coil 223 of relay 204,-to the negative batterycon- 9 nection 224. The making of the connection at relay contacts 226(FIG. 6) has no efiect at this time because the connection at relaycontacts 199 has been broken by the action of the relay 191.

Thus, when relays 191 and 204 (both shown in FIG. 4) are energized, therelay 100 is normally de-cnergized; except when relay 250 (FIG. 4)(later to be more fully described) is energized. The waning of thecurrent in relay 100 allows the contact 115 (FIG. 6) to be broken withina short time and deenergizes the relay 63 (FIG. 4). This causes thepulsing circuit including relays 61, 62, and 63 to again beginoperation, as described previously.

DIALING As the pulsing circuit previously described again operates, therelay 63 is alternately energized and de-energized. This accomplishesthe alternate breaking and making of contact 67 (previously described),the alternate making and breaking of the contact 92, the alternatemaking and breaking of the contacts 93 (FIG. 6), and the alternatebreaking and making of the contact 94.

The making and breaking of the contact 92 alternately closes and opens aconnection from the tip wire of the line of the calling number(connected to ground) to the ring of the line of the calling number(connected to negative battery), the circuit including the spring 123(connected to the tip wire of the line of the calling number) (FIG. 5),the lead 124, lead 125, tip spring 126, lead 127, lead 128, lead 129(FIG. 4), resistance 131, lead 132, subsidiary switch 133 of toggleswitch 32, spring 134, lead 135, spring 136 (FIG. 5), tip spring 137, ofthe pulse check jack 52, lead 138, lead 139 (FIG. 4), lead 165, relaycontact 92 (which as just stated, is alternately closed and opened byrelay 63), lead 166, lead 142, lead 143 (FIG. 6), and lead 144, uppercoil 145 of relay 146, lead 147, lead 148, lead 149, spring 151, ringspring 152 of pulse check jack 52, lead 153, lead 154, relay contact155, lead 156, lead 157, lead 158, relay contact 159, lead 161, lead162, ring lead 163, and the ring spring 164 or" the calling number jack51 which is connected to the ring wire of the line equipment and thus tonegative battery. The fact that relay 100 at this time is de-energizedcauses the relay contact 112 to remain open so that the circuitpreviously described from the spring 123 through the relay contact 112to the ring spring 164 is ineflective. Thus pulses are created in theequipment associated with the calling number just as if the callingnumber equipment were manually dialed.

OPERATION OF STEPPING SWITCH MAGNET 231 As stated above under theheading Dialing, as the relay 63 (FIG. 4) is alternately energized anddeener gized, it also accomplishes the alternate making and breaking ofthe contact 92; alternately makes the circuit complete from the ring 164to the spring 123 of the calling number jack 51 and breaks such circuit;and thus alternately closes and opens the circuit for the calling numberequipment creating a pulse in the calling number equipment exactly thesame as if the calling number equipment were manually dialed. Thispulsing would continue indefinitely were it not for the means providedfor interrupting it by means of apparatus now to be described. Thismeans includes some of the switches, jacks, relays and wiring previouslydescribed. It also includes the minor stepping switch magnets 231 (FIG.6) and 232 (FIG. 7), the stepping switch 233 including contact bank 233aof stepping switch 233 (FIG. 6), the stepping switch 234 including itscontact bank 234a, the stepping switch 235 (FIG. 7), including itscontact bank 235a, and the stepping switch 236 including its contactbank 236a, the digit switches 17 to 26 inclusive (FIGS. 6 and 7), andthe trunk off switch 27 (FIG. 7), and relays 250 (FIG. 4) 297 (FIG. 4),298 (FIG. 5), and 299 (FIG. 5) (the function of all of which is later tobe more fully described).

Before dialing is started, the pulse generator starting switch 31 (FIG.4) is closed, the originate call switch 32 is closed, and plugs areinserted in the calling number jack 51 (FIG. 5), the called number jack54, and the battery and ground jack 55 (FIG. 4). Relay 63 is energizedas is relay 100. Relays 191 and 204 are not energized, nor are relays146 (FIG. 5), 250 (FIG. 4), 297 (FIG. 4), 298 (FIG. 5) and 299. Relaycontacts 206 (FIG. 7) are closed (because relay 146 (FIG. 5) is not energized). Relay contacts 209 (FIG. 7) are closed (because relay 298 (FIG.5) is not energized). Relay contacts 117 (FIG. 6) are closed becauserelay (FIG. 4) is energized. Relay contacts 116 (FIG. 6) are openbecause of relay 100 (FIG. 4), and relay contacts 94 (FIG. 6) are openbecause of relay 63 (FIG. 4). Therefore no current flows to minor switchmagnet 231 (FIG. 6). Now when the dial start switch 33 (FIG. 4) isclosed it closes the circuit through and energizes the relay 191 whichin turn energizes the relay 204 through contact 195 as previouslydescribed and this breaks the connections at relay contacts and 193 tode-energize the relay 100. This in turn breaks the connection at relaycontact (FIG. 6) and de-energizes the relay 63 (FIG. 4). With the relay204 energized and with relays 63 and 100 de-energized, and with relays146 (FIG. 5) and 298 deenergized, a circuit is formed from the mainground 205 (FIG. 7) to the minor switch magnet 231 (FIG. 6). Re laycontacts 206 (FIG. 7) are closed (because the relay 146 (FIG. 5) isde-energized), contacts 209 (FIG. 7) are closed because the relay 198(FIG. 5) is de-energized), contacts 94 (FIG. 6) are closed (because therelay 63 (FIG. 4) is de-energized), contacts 116 (FIG. 6) are closed(because the relay 100 (FIG. 4) is de-energized) and contacts 196 (FIG.6) are closed (because the relay 191 (FIG. 4) is energized). Therefore acircuit is formed from the ground 205 (FIG. 7) through contacts 206, theleads 207 and 208, contacts 209, the leads 211 and 253 (FIG. 6), thelead 266, contacts 94, the leads 277 and 278, contacts 116, the lead279, contacts 196, the leads 281, 282, and 283, through the minor switchmagnet 231 to the negative battery 284. This causes the movable wiper251, associated with the bank 234a, and the movable wiper 252,associated with the bank 233a, each to advance one step.

The energizing of minor stepping switch magnet 231 moves the rotary offnormal contacts 280 to an on position. Contact 280 will now stay closed,until positively released by the associated release magnet 384, througha mechanical locking arrangement.

OPERATION OF STEPPING SWITCH MAGNET 232 Another circuit is formed underthe same condition which circuit may be traced from main ground 205(FIG. 7) through contacts 206 (closed because relay 146 is notenergized), leads 207 and 208, contact 209 (closed because the relay 298is not yet energized), lead 211, lead 253 (FIG. 6), lead 254, contact118 (closed because the relay 100 has been de-energized), leads 255,256, contact 197 (closed by operation of the relay 191), lead 257,contact 258 (FIG. 7) (closed because the relay 298 is not yetenergized), leads 259, 261, 262, to minor switch magnet 232 and thenceto negative battery connection 263. This energizes minor switch magnet232 and thus causes the movable wiper 264, associated with the bank235a, and the movable wiper 265, associated with the bank 236a, each toadvance one step. It also causes rotary oif normal contact 296 to bemoved to a closed position, which will stay closed, until released bythe associated release magnet 445, through a mechanical lockingarrangement.

DE-ENERGIZING OF MINOR SWITCH. MAGNET 231 When during the pulsingoperation, relay 63 (FIG. 4) is energized, contacts 94 (FIG, 6) arebroken thereby and then current ceases to flow to the magnet 231 (FIG.6) and the minor switch stepping lever releases. However,

the movable contact wipers 251 and 252 are then held in their newpositions mechanically and do not go back to their initial position.Neither is the rotary off normal contacts 280 released to its oilposition, but remains closed until positively released, by the releasemagnet 384. When the relay 63 is again de-energized in the pulsing cyclethe magnet 231 is again energized and these movable wipers 251 and 252are again advanced one step. Therefore as the pulsing cycle operates toenergize and de-energize the relay 63, the movable contact wipers 251and 252 are each advanced one step for each pulse created by the pulsingcircuit. However, it should be noted that contacts 94 are not in thecircuit controlling minor switch magnet 232 and there is at this time nofurther stepping of movable wipers 264 and 265, associated with banks235a and 2363..

Thus during the pulsing operation, the relays 191 (FIG. 4) and 204 areenergized while the relays 100, 250, 146, 298 and 299 are not energizedand relays 61, 62 and 63 are alternately de-energized and energized.Each time the relay 63 is energized the contact 94 is broken and thecontacts at 93 are closed. When the relay 63 is tie-energized, thecontacts at 93 are broken and the contact at 94 is again made. Thus, foreach pulse a circuit is formed through the minor switch stepping magnet231 which steps the wiper 252 on the contact bank 233a and steps thewiper 251 upon the contact bank 234a.

If it is desired to test the correctness of the pulsing operation, apulse meter is plugged into pulse check jack 52 by which the correctnessof the pulses can be determined.

GENERAL DESCRIPTION OF FIGURE 8 Now for the purpme of simplifying thedescription of the next operation, I refer to FIG. 8 in which is shown asimplified diagram showing a portion of the diagram of FIGS, 6 and 7,but utilizing onily three of the digit switches. Thus, of the digitswitches 17 to 26 inclusive, only the switches 17, 18 and 19 are shown,the others being omitted for simplification and clarity. The trunk offswitch 27 and the stepping switches 235 and 236 have been simplified andare designated respectively 27b, 235b and 236b. Digit switch 17 is setfor dialing two pulses; digit switch 18 is set for dialing one pulse anddigit switch 19 is set for dialing three pulses. The trunk off switch27a is set for a limit of dialing three digits. The movable wipers 251and 252 are shown in the position they assume after they have beenstepped by the minor stepping switch magnet 231 to their secondcontacts. The movable contact wipers 264 and 265 are shown in theposition they assume after they have been moved by the minor steppingswitch magnet 232 to their first contacts. These modifications are shownmainly for the purpose of simplifying the explanation.

Referring further to FIG. 8 for a more detailed description thereof, itmay be seen that I have shown digit switches 17, 18 and 19, the bankcontacts of the stepping switches 233, 234, 245b and 236b, the trunk offswitch 27b and the movable contact wipers 251, 252, 264 and 265. Thebank contact 234a of the stepping switch 234 has fixed contacts 301,302, 303, 304, 305, 306, 307, 308, 309 and 310, with which the movablecontact wiper 251 contacts in turn. The bank contact 233a of thestepping switch 233 similarly has fixed contacts 311-320, inclusive. Thedigit switch 17 has fixed contacts 321-330, inclusive. The digit switch[17] has fixed contacts 331340, inclusive, and the digit switch 19 hasfixed contacts 341-350, inclusive. The digit switches 17, 18 and 19 areprovided with movable contact wipers 351, 352 and 353 respectively. Thetrunk off switch 27b is provided with a movable contact wiper 354 andwith fixed contacts 355, 356 and 357. The stepping switch 235b isprovided with a movable contact wiper 264 and with fixed contacts 361,362 :and 363. The stepping switch 236b is provided with a movablecontact wiper 265 and with fixed contacts 364, 365 and 366.

As shown in FIG. 8, the movable contact wiper 251 has been advanced tothe contact 302, the movable contact wiper 252 has been advanced to thecontact 312, and the contact 280 has been closed by the stepping switchmagnet 231. The contact 296 has been closed by the stepping switchmagnet 232. The wipers of the digit switches 17, 18 and 19 have been setso that the wipers thereof contact the corresponding fixed contact tolimit its pulsing to the number set to be dialed consisting of the threedigits 2, 1, 3, in order.

DETAILED OPERATION OF STEPPING SWITCH 231 With relays 204 and 191 (FIG.4) energized, but with the relays 100, 250, 297, 146 (FIG. 5), 298 and299 de-energized and with the pulsing relays 61, 62 and 63 (FIG. 4)alternately energized and de-energized in the pulsing operation,whenever relay 63 is de-energized a circuit is formed from the mainground 205 (FIG. 7) through the relay contact 206, lead 207, lead 208,relay contacts 209, lead 211, lead 253 (FIG. 6), lead 266, contact 94,lead 277, lead 278, contacts 116, lead 279, contact 196, lead 281, lead282 (see also FIG. 8), lead 283, stepping switch magnet 231 to negativebattery 284. This energizes the stepping switch magnet 231 and thussteps the movable wipers 251 and 252 to fixed contacts 301 and 311.

DETAILED OPERATION OF SWITCH 232 Under the same conditions (i.e. withrelays 204 and 191 energized but with relays 100, 146, 250, 298 and 299de-energized another circuit is formed as follows: From the main ground205 through relay contacts 206, the leads 207 and 208, relay contacts209, the leads 211, 253, 254, relay contacts 118, the leads 255 and 256,contacts 197, lead 257, contact 258 (FIG. 7), leads 259 (see also FIG.8), 261 and 262, stepping switch magnet 232 and nega tive batteryconnection 263. This energizes the minor switch magnet 232 which stepsthe movable conitact wipers 264 and 265 to contact with fixed contacts361 and 364 (FIG. 8) and also closes the rotary off normal contacts 296.The effect of this operation will appear later.

FURTHER OPERATION Inasmuch as contact 301 and contact 311 of steppingswitches 234 and 233 do not complete any circuit (ground must bereceived by wiper 251 from wiper 264), the pulsing continues and therelay 63 is in due course again energized. When it is energized again itbreaks the circuit by opening the contacts 94, but when it is againde-energized it completes another circuit in the same way as explainedabove through the stepping switch magnet 231 and again steps the movablecontact wiper 251 and movable contact wiper 252 to the fixed contacts302 and 312. When the relay 63 is again energized it closes the contacts93 and forms a circuit as is shown in FIG. 8 as follows:

From the main ground 205 (FIG. 7) to the contact 206, lead 207 and lead208, contact 209, lead 211, lead 253 (FIG. 6), lead 266, contact 93, thelead 281, lead 292 (see also FIG. 8), lead 293, lead 294, contact 296(which has been closed, as described above, by the stepping switch 232),lead 295, the movable contact wiper 264 of the stepping switch 235b(FIG. 8), the fixed contact 361, the lead 391, lead 392, lead 393, themovable contact wiper 351 which is set, as shown, in contact with thefixed contact 322, said fixed contact 322, the leads 394, 395, 396, tothe fixed contact 302, the movable contact wiper 251, leads 371, 372 and373, relay 250 (FIG. 4), and a negative battery connection 374. Thisenergizes the relay 250 which closes the contact 375 and connects theground at 376 through contact 375 and leads 377 and 109 to relay andnegative battery 111. This energizes relay 100 which now closes thecontacts at (FIG. 6), connecting the ground at 120, through the relay 63(FIG. 4) to negative battery connection 86, to hold the relay 63 andstopping the pulsing until after the relay 250 is again deenergized.Pulsing is also stopped to the equipment attached to the calling numberjack 51 through contacts The energization of relay 100 breaks thecontact at 118 (FIG. 6) and closes the contact at 117. The breaking ofthe contact at 118 breaks the circuit through stepping switch magnet 232(FIG. 7). This de-energizes the stepping switch magnet 232 but does notreturn the movable contact wipers 264 and 265 to their off position,these wipers being held against contacts 361 and 364 (FIG. 8) bymechanical means. Nor does it release the contacts 296 which is held ina closed position by mechanical means until released positively by meanslater to be described. The closing of the contacts 117 (FIG. 6) createsa circuit from the main ground at 205 (FIG. 7) through the contacts 206,leads 207, 208, contacts 209, leads 211, 253 (FIG. 6), 254, contacts117, leads 378, 379, 381, contacts 280, lead 383, release magnet 384, tonegative battery at 385. It must be remembered that the contact at 280was closed by operation of the minor switch 231 and has remained closeduntil now when it will be opened by operation of the release magnet 384.

As stated above, the energizing of the relay 100 (FIG. 4) energizes therelay 63 (FIG. 6) and holds that relay energized from the ground 120.The energizing of the relay 63 breaks the connection at contacts 94 andmakes a connection at contacts 93. The breaking of the connection atcontacts 94 de-energizes the stepping switch magnet 231 as abovedescribed and with the result above described.

EFFECT OF OPERATION OF RELEASE MAGNET 384 The circuit through therelease magnet 384 energizes that magnet and the operation thereofreturns the wipers 251 and 252 from the position shown in FIG. 8 to thenormal position shown in FIG. 6 and operates the RON contacts 280 to itsoff position, thus breaking the connection at contacts 280 until thestepping switch magnet 231 again is energized. The circuit from theground to relay 250 through the contacts 206 (FIG. 7), leads 207, 208,contacts 209, leads 211, 253 (FIG. 6), 254, contacts 117, leads 378,386, 387 (FIG. 7), 388, movable contact wiper 265 and contact 366 is notcompleted because the wiper 265 has not yet reached the contact 366(FIG. 8) which is connected to the movable wiper 354 of the trunk offswitch 27a.

As stated above, the operation of release magnet 384 releases themovable contact wiper 251 and movable contact wiper 252 back to theposition shown in FIG. 6. This breaks the contact between the wiper 251and fixed contact 302 and thus breaks the circuit from ground 205 tonegative battery connection 374 through relay 250 and de-energizes relay250.

DE-ENERGIZATION OF RELAYS 250, 100 AND 63 In turn, the de-energizationof relay 250 (FIG. 4) breaks the contact at 375 and de-energizes therelay 100. However, the charging of the capacitor 248 in series withrelay 100, holds the relay 100, for a short interval before it isde-energized. Nevertheless, the removal of the holding ground at 37 fromthe relay 100 allows relay 100 to release after a short period of timeas explained above. Relay 100 in releasing, opens contacts 115 andremoves the ground to relay 63, allowing relay 63 to de-energize. Therelease of relay 100 closes the relay contacts 118 (FIG. 6) and thusoperates stepping switch magnet 232 gized. The relay (FIG.

again. This moves the contact wiper 264 to fixed contact 362 (FIG. 8),preparing it to receive the next digit dialed. The de-energization ofrelay 100 also opens the contacts 117 (FIG. 6). This has no real efiectat the moment because the circuit from the ground 205 through contacts117 and through magnet 384 to negative battery 385 was broken atcontacts 280 when release magnet 384 was ener- 4) in releasing alsoremoves the short from across the pulsing contact 92 at relay 63. Relay63 in being de-energized breaks the contact at 93 and makes the contactat 94. The making of the contact at 94 (as explained above) energizesthe stepping switch magnet 231 again to advance the movable contactwipers 251 and 252 to the first contacts 301 and 311. Thede-energization of the relay 100 also allows the relay contacts 118 toclose. This operates the magnet 232 as explained above to step themovable contact wiper 264, stepping it this time from the fixed contact361 to the next fixed contact 362.

FURTHER STEPPING BY STEPPING SWITCH MAGNETS 231 AND 232 As stated above,when the release magnet 384 is operated as described above, it not onlybreaks the contact 280 but also returns the movable wipers 251 and 252back from the position shown in FIG. 8 to the position shown in FIG. 6as described above. The movement of the movable wiper 251 from the fixedcontact 302 breaks the circuit including the relay 250, thus openingtherelay contacts 375 and removing the ground from the relay 100 so thatthe relay 100 is dc-energized (after a short delay due to the chargingof the condenser 248). The de-energization of the relay 100 allowscontacts to open and thus breaks the connection from the ground to therelay 63. It closes the contacts 118 and thus operates the steppingswitch magnet 232 again. Relay 63 is thus de-energized and the pulsingaction again starts. Deenergization of the relay 63 closes contacts 94and operates the magnet 231 as described above and causes the wiper 251to be moved to the fixed contact 301. When the relay 63 is againenergized in the pulsing action, it closes the contact 93. This createsa circuit as follows: From the main ground at 205 (FIG. 7) through therelay contacts 206, the leads 207 and 208, the relay contacts 209, lead211, lead 253 (FIG. 6), lead 266, the relay contacts 93, leads 291, 292,293 (FIG. 7), 294, contacts 296, lead 295, movable contact wiper 264,fixed contact 362 (FIG. 8), leads 401, 402, 403, movable contact wiper352, fixed contact element 331, leads 404, 405, 406, fixed contactelement 301, movable contact wiper 251, leads 371, 372, and 373, throughrelay 250 (FIG. 4) to negative battery connection 374. This energizesrelay 250, which again in turn, as described above, energizes first therelay 100, then the relay 63, then the release magnet 384, then breaksthe contact between the movable wiper 251 and the fixed contact 301, andbreaks the contacts at 280. Then successively relay 250 is de-energized,the relay 100 is de-energized, the magnet 232 is operated to step thewiper 264 to the contact 363, and the relay 63 is de-energized. Thisagain forms a circuit through the stepping switch magnet 231 whichcloses the relay contacts 280 and moves the movable wiper 251 to thecontact 301. The relays 61, 62 and 63 are successively energized in thepulsing cycle and the energizing of the relay 63 breaks the contact at94 de-energizing the magnet 231. As the pulsing continues, the relay 63is de-energized and the contacts at 94 are again closed and the magnet231 is again energized. This steps the movable wiper 251 to the contact302, the continued pulsing energizes the relay 63, de-energizing themagnet 231, and again as relay 63 is de-energized, again energizes themagnet 231 which steps the movable wiper 251 to the fixed contact 303.When the relay 63 is next energized, a circuit is then formed from themain ground 205 (FIG. 7) through the relay contacts 206, the leads 207and 208, the relay contacts 209, lead 211, lead 253 (FIG. 6), lead 266,the relay contacts 93, leads 291, 292, 293 (FIG. 7), and 294, contacts296, the movable wiper 264, the fixed contact 363 (FIG. 8), leads 407,488, and 499, the movable wiper 353, the contact 343, lead 411, lead412, lead 413, the fixed contact 303, movable wiper 251, leads 372, 373,relay 250 (FIG. 4), and the negative battery connection 374. Relay 250energizes as explained above.

COMPLETION OF DIALING When relay 250 energizes, the relays 180 and 63energize as before. However, there is this difference. The energizationof the relay 108 closes relay contacts 117 which energizes the magnet384 and returns the movable wipers 251 and 252 to the position shown inFIG. 6 at the same time that it breaks the contact at contacts 280 asbefore. However, relay 250 is not de-energized by the return of movablewiper 251 to the position of FIG. 6 because another circuit is providedwhich holds relay 259 energized. This circuit is formed from the mainground 265 (FIG. 7) through the relay contacts 206, the leads 207 and208, the relay contacts 289, leads 211 and 253 (FIG. 6), lead 254,contacts 117, the leads 378, 386, 387, 388, movable wiper 265, fixedcontact 366 (FIG. 8), the leads 414, 415, the fixed contact 357, themovable wiper 354, the leads 416, 417 and 418, and 373 through the relay256 (FIG. 4) to the ground 374. This holds the relay 250 energized andthrough it the relays 109 and 63, and the pulsing stops.

, The energizing of the relay 1% (FIG. 4) operates the relay contacts119 (FIG. 6) and thus closes the circuit from the ground 168 (FIG. 6),through contacts 119, and through the leads 171, 172 (FIG. 7), 173, 174,175 and 176 to the alarm 45 and to the negative battery connection 177.This sounds the alarm continuously.

However, the device has now pulsed the number which was set on the digitswitches 17, 18 and 19, sending these pulses through the calling numberjack (i.e. it has dialed the number 213 which we are assuming is thecalled number). The equipment associated with number 213 sends ringingcurrent (A.C.) on the called number attached to the called number jack54 and the ringing (A.C.) current is transmitted from the called numberjack 54 through leads 421, 422, 423, 424, 425 (through the capacitors426 or 426a), through lead 427, relay contacts 428 (FIG. 4) and leads429, 429a and 429b, through the A.C. relay 297 to the ground at 431.This operates the A.C. relay 297 which in turn closes the relay contacts432 and connects the ground at 433 through said relay contacts 432 andleads 434 and 435 (FIG. 5) to the relay 298, and through it to negativebattery at 436. During all this time the calling number equipment hasbeen seized by the circuit inasmuch as whenever the relay 63 isenergized, the relay contacts 92 (FIG. 4) are closed, creating a circuitthrough the calling number equipment. The intervals between pulsescreated by the cycling of relays 61, 62 and 63 are not sufiicient torelease the calling number. However, the energization of relay 298 (FIG.5) breaks the relay contact 159 long enough to release the callingnumber equipment which in turn releases the equipment associated withthe called number, thus removing the ringing current from the callednumber circuit, and releases relay 191, because ground is removed fromthe sleeve of the calling number jack 51. The cessation of the ringingcurrent from called number jack 54 releases relay 297 This breaks therelay contacts 432 and releases the relay 298. However, while the relay298 was energized it not only (1) opened the relay contacts at 159, butalso (2) made a connection at relay contacts 438, (3) broke a connectionat relay contacts 439, (4) broke relay contacts at 209 and 258, and (5)made a connection at a relay contact 441. The breaking of the contact at209 breaks the circuits through relay 204 and releases that relay. Whenthe relay 298 releases, it restores the connections at contacts 159,437, 439, 209 and 258, and breaks the contacts at 438 and 441. Thisrestores the routiner to the condition shown in FIGS. 4, 5, 6 and 7.

The operation of relay contacts 441 (FIG. 7) closes a circuit from themain ground 295 through the relay contacts 206, leads 207 and 288, therelay contacts 441, the leads 442, 443 and 444, to release magnet 445and through it to negative battery at 446. This energizes the releasemagnet 445 and moves the movable contact wipers 264 and 265 back to theposition shown in FIG. 7. It also operates the rotary off normalcontacts 296 to its open position.

The release of relay 297 opens contact 432 and thus releases relay 298.As soon as the relays 63, 186, 251., 297 and 293 have released, theapparatus is back in the same condition that it was when dialing wascommenced, and the dialing is ready to be repeated.

ANSWER CONNECTOR FEATURE Relay coil 146 is connected as previouslydescribed, to the tip 123 of calling number jack 51 and to the ring 164thereof, thus drawing current. But relay 146 is a 2-coil (both coils onthe same core) relay and is so wired that the magnetic field set up byboth coils oppose each other, thus preventing the relay armature fromoperating. As long as the tip 123 has positive potential and the ring164 has negative potential applied to them, relay 146 cannot operate.There is, however, a relay in the connector switch of the switch trainof the telephone equipment called the answer relay. This relay operateswhen a short is applied to the answer side of the connector switch. Thisrelay, when operated, will reverse the polarity of the calling numbertip 123 and ring 164. When this reversal occurs, relay 146 will operateas the magnetic field of its 2 coils will now aid each other. When relay146 operates, it breaks contacts at 155 and 206, and makes contacts at494 and 495. The breaking of the contact at 155 releases the telephoneequipment of the calling number connected to the calling number jack 51.It also breaks the circuit through and thus de-energizes the relay 146and allows the contacts to again close. The closing of the contacts 494connects a ground at 493 to the relay 100 to energize it, thus holdingthe relay 63 energized. The breaking of the contacts at 296 releases allequipment dependent on the main ground 205. Relay 146 will not operateuntil relay 299 operates and the connector switch is answered. Thisaction takes place as described hereinafter.

The connector switch is that switch in the train of the telephoneequipment which receives the last three digits of the called number. Itremoves the polarity that exists on the called number tip and ring, asexplained above, and applies A.C. ringing current. This ringing currentis applied in short periods of time. In the silent period it againsupplies a positive and negative potential to the called number tip andring, this potential being applied through the answer relay.

When the answer connector switch 37 (FIG. 4) on the routiner is operatedto its on position, relay 299 (FIG. 5) will also be operated from theground 481 (FIG. 4) at the toggle switch 37, over leads 482 and 483through relay contacts 438 through leads 484, 485 and 486, to relay 299,and to negative battery potential 487. This action takes place afterrelay 297 has been operated from the A.C. current from the connectorswitch and relay 293 has been operated from relay 297. Another circuitis formed from the ground 481, over leads 482 and 483, contacts 433,leads 484, 485, 488 and 489, through connector answered lamp 42, and tonegative ground at 490.

Relay 298 opens the relay contacts 159, thus starting to release theequipment attached to the calling number jack 51, but relay 299 closesrelay contact 491 which closes a multiple short to the same callingnumber jack 51 tip and ring, this action being too fast for theequipment ahead of the calling number jack 51 to release. Relay 299 alsocloses relay contacts 492 through a 500 ohm resistor 493 to the answerside of the connector switch. The connector answered lamp 42 thenindicates that the routlner relay 299 is to furnish this 500 ohm short,and further that the routiner is not to re-cycle until the telephoneequipment connector switch has reversed the polarity back to the callingnumber jack 51, allowing relay 146 to operate. If this condition failsto exist, then the routiner will not recycle since relay 146 starts there-cycling condition when the answer connector toggle switch 37 isoperated. If the routiner does not re-cycle, the alarm buzzer 45 willsound continuously.

The operation of the relay 297 (FIG. 4) (indicating that a call has beencompleted and that ringing current is being received on the callednumber jack 54) operates the calls completed meter as follows: The relay297 operates the relay contacts 432 to connect the ground 433 throughthe relay contacts 432 and the leads 447, 448, 449, 451, 452, 453 (FIG.5), 454, 455, to meter 44 and through it to negative battery at 456.

When the relay 298 is released, thus placing the device in condition toinitiate a new call as explained above, it breaks the contact at relaycontacts 441 (FIG. 7), and closes the contact at relay contacts 209.This closes a circuit from the ground 205 through the relay contacts206, the leads 207 and 208, the contact 209, leads 211, 212 (FIG. 6),213 (FIG. 4), the relay contacts 195, lead 214, the leads 461, 462 (FIG.6), 463 (FIG. 7), 464 (FIG. 5), and through meter 43 to negative batteryat 465. This causes the calls originated meter to register.

Leads 501 and 502 connect answer connector toggle switch 37 with thejunction of leads 207 and 208. Relay contact 504 controlled by relay 297is connected on one side to relay 462 and on the other through leads505, 506, and 507 and through relay 297 to negative battery connection508. Leads 511 and 512 connect C lead hold toggle switch 34 with answerconnector toggle switch 37. Lead 513 connects the junction of leads 511and 512 with the junction of leads 212, 213 and 219. Lead 514 connects Clead hold toggle switch 34 with relay contacts 225. Leads 515 and 516connect answer connector toggle switch 37 with the junction of leads 156and 157. Lead 518 connects lead 161 with relay contacts 491 and lead 519connects said relay contacts 491 with the junction of leads 157 and 158.Lead 521 connects relay switch 492 with the junction of leads 421 and422, and lead 522 connects relay contacts 492 with resistor 493. Theresistor 493 and the lead 522 are in turn connected by a lead 523 withrelay contacts 495. A lead 524 connects relay switch 439 with relaycontacts 525 and relay switch 525 is also connected by lead 526 with thejunction of leads 172 and 173. Lead 527 connects the junction of leads161 and 162 with answer connector toggle swtich 37. Relay contacts 528at times connect ground 529 with lead 418 and relay contacts 531 attimes connect ground 532 with lead 418.

In the event that the dialing is not completed on account of a failureof the telephone equipment with which it is connected, the equipmentnormally remains seized and the alarm sounds continuously. Thesupervisor then investigates the telephone equipment and corrects thefaulty condition. Thereafter he closes the manual release switch 36(FIG. 4). This connects the lead 448 to the ground 471 of switch 36 anddisconnects the lead 449 from lead 451. This operates the relay 298 torestore the equipment to operating condition as previously described andprevents the calls completed meter 44 from registering a falseregistration.

The equipment attached to the calling number jack 51 (FIG. 5) is seizedby a short across the tip ring leads. When the connector switch in theswitch train of the calling number puts the A.C. current forward to thecalled number jack 54 (assuming the correct number has been reached),the relay 297 (FIG. 4) will operate from this A.C. current. The relay297 now operates relay 298 (FIG. 5). The relay 298 opens contacts 159which closed a short to the tip ring leads, of the calling number jack51. The opening of this short releases the equipment attached to thecalling number jack 51. This equipment in releasing removes the groundfrom the sleeve 181 of the calling number jack 51. When this occurs,relays 191 and 204 (FIG. 4) will release. The relays and 250 were alsoenergized when relay 298 operated. Relay 298 now is released becauserelay 297 is released, no longer having A.C. current applied to it sincethe connector switch has been released by the removal of the short asexplained above. After a short period of time, relays 100 and 250 willrelease. When relay 298 (FIG. 5) releases, it closes the short 159 tothe telephone equipment attached to the calling number jack 51, thusseizing this equipment again. Relays 191 and 204 (FIG. 4) now operatefrom the ground on the sleeve 181 (FIG. 5) of the calling number jack51. The routiner will now start to send the number being called again.

GENERAL OPERATION The operation has been explained in the description ofthe device. However, a resum thereof at this point may be helpful.

Before the routiner is started for operation all seven toggle switchesare set to their olf position, then plugs are inserted in the batteryand ground jack 55 (FIG. 4), the calling number jack 51 (FIG. 5), thecalled number jack 54, and the switches 17-26 inclusive (FIGS. 6 and 7),are set to the various digits contained in the selected calling number.The trunk off switch 27 (FIG. 7) is set to the number corresponding tothe total number of digits contained in the selected number to bedialed. Then the pulse generator start switch 31 (FIG. 4) is turned toits on position. This starts the three-relay (61, 62, 63) pulsegenerator running. The relays are allowed to run for a period of 15minutes or more to warm up, then the originate call switch 32 is turnedto its on position. Then the dial start toggle switch 33 is turned toits on position. Relays 191 and 204 operate, as explained above, fromthe ground on the C-lead 181 (FIG. 5) of the calling number 51. Relay100 (FIG. 4) releases after a short period of time depending upon thesetting of the 10,000 ohm variable resistance 249 which is in serieswith the 500 mf. condenser 248. When the relay 100 releases it removes ashort from relay 63. Relay 63 then begins to create dial pulses whichoperate the calling number equipment the same as a subscribers dialwould do. As relay 63 pulses the calling number equipment it also stepsstepping switch magnet 231 (FIG. 6) one step for each pulse. Whenstepping switch magnet 231 reaches its bank contact corresponding to thesetting of digit switch 17 the relay 250 (FIG. 4) operates.

Relay 250 operates relay 100. Relay 100 shorts the pulsing contacts ofrelay 63 and also stops the pulse generator relays 61, 62 and 63 fromoperating continuously. This is done so that the first pulse of thedigit is just as good (i.e. long) as any succeeding pulse of the digit.Relay 100 also releases stepping switch magnet 231 (FIG. 6) to itsnormal position. Stepping switch magnet 231 in releasing, releases relay250 (FIG. 4). Relay 250 in releasing, removes the holding ground fromrelay 100. After a short period of time as explained above, relay 100will release. Relay 100 in releasing removes the short from across thepulsing contacts of relay 63 and removes the holding ground from relay63. It also steps stepping switch magnet 232 (FIG. 7) to its next bankcontact.

Relays 61, 62 and 63 (FIG. 4) now start operating again. Relay 63 againstarts pulsing the calling number equipment and the stepping switch 231(FIG. 6). When stepping switch 231 reaches its bank contactcorresponding to the setting of digit switch 18, relay 250 (FIG. 4) willoperate. The procedure listed in the last paragraph is then repeated.

The procedure listed in the last paragraph will be repeated for eachdigit corresponding to the settings of all of the digit switches.When-stepping switch magnet 232 (FIG. 7) reaches its bank contactcorresponding to the setting of the trunk off switch 27, relay 250 (FIG.4) will be locked up after it is operated from stepping switch magnet231 (FIG. 6). The total number of digits corresponding to the callednumber as set up on the digit switches has now been dialed. If dialinghas proceeded correctly the connector switch will be connected to thenumber that the plug plugged into the called number jack 54 (FIG. 5 isclipped to.

The connector switch of the dialed telephone equipment now forwards A.C.generator current to the routiner by the called number cord on eitherthe tip or sleeve of the cord. The relay 297 (FIG. 4) will operate fromthis A.C. generator current. The relay 297 operates relay 298 (FIG. 5).Relay 298 opens the tip ring short to the calling number equipment byopening contacts 159, releasing the equipment. Relay 298 also releasesstepping switch magnet 232 (FIG. 7) which in turn releases relays 100and 250 (FIG. 4). Relay 298 (FIG. 5) also releases relays 191 and 204(FIG. 4). Relay 298 now releases, because the calling number equipmentis released. The routiner is now in a normal condition ready to re-dialthe called number as described above.

If the 1000 ohm loop toggle switch 35 (FIG. 4) is in its off position,the tip ring loop consists of 1,060 ohms. If this toggle switch isoperated to its on position, the tip ring loop will be 5 60 ohms. Thesetwo resistance loops will duplicate the conditions normally encounteredon the subscribers line.

If the routiner should encounter an open tip ring loop in the callingnumber equipment, the calling number equipment can be locked in thiscondition by operating the C-lead hold toggle switch 34 (FIG. 4) to itson position before the routiner starts dialing. The maintenancepersonnel can therefore easily locate the fault in the tip ring loop.

If the answer connector toggle switch 37 is operated before the routinerstarts dialing, the routiner will not be released as soon as the relay298 (FIG. 5) operates, but must wait until relay 146 is operated by thetip ring lead reversal by the connector switch in the calling numberequipment. The answer connector lamp 42 visually indicates thiscondition.

The manual release toggle switch 36 can be used to release the routinerto its normal position at any desired time. It is usually used if awrong number or an incomplete dialing cycle has been reached.

If it is desired to listen on the line while dialing, a receiver can beplugged into the receiver jack 53. This is useful to check for any busyor calling number equipment butt-ins that may be encountered.

This routiner may be used to dial from any part of the switch train usedin the calling number equipment by attaching the tip ring sleeve wiresof the cord used for the calling number equipment to the tip ringC-leads respectively of the desired switch. However, for each switcheliminated in the train, the trunk off switch 27 (FIG. 7) and the digitswitches 17-26 (FIGS. 6 and 7) must be set accordingly. For instance, ifthe routiner is to be attached to the second switch in the train, thefirst digit of the number is to be dropped and the digit switch 17should be set to the second digit of the number, the digit switch 18 tothe third digit of the number, etc. The trunk olf switch 27 would be setto the total number of digits left to be dialed in the number. If theroutiner is to be attached to the connector switch then a maximum ofthree digits could be dialed and only switches 17, 18 and 19 would beused. The trunk 01f switch would be set to three.

If the routiner is to be used to dial toll codes within the exchange,then a ring out trunk termination will have to be provided as the callednumber trunk in place of the called number line equipment used in thelocal subscriber equipment part of the exchange.

The audible alarm will sound intermittently as long as dialing isproceeding. This will give the maintenance personnel an audibleindication that dialing is proceeding.

The readings on the calls originated and calls completed meters willshow the calls tried and the calls correctly completed and bysubtracting the calls completed meter reading from the calls originatedmeter reading, the number of lost calls that the subscribers would bereceiving is known.

It is to be understood that the above described embodiments of myinvention are for the purpose of illustration only and various changesmay be made therein without departing from the spirit and scope of theinvention.

I claim:

1. In a telephone exchange system having a plurality of subscriberslines and pulse responsive equipment operable to establish a connectionbetween any two subscribers lines, a testing device having, in additionto a group of manually operated individual digit indicating rotaryswitches, a manually operated total digits indicating rotary switch, anelectrically operated rotary switch to select, in sequence, the manuallyoperated individual digit indicating rotary switches, an electricallyoperated rotary switch to integrate the total pulses indicated by themanually operated individual digit indicating switches, connectible toany twoof the said subscribers lines, a group of relays to create pulsesof proper speed and ratio to operate said pulse responsive equipment forthe purpose of establishing a connection between the said two selectedsubscribers lines, and means comprising a group of contacts controlledby said relays, a lamp, and connections between said contacts and saidlamp to visually indicate that the pulse creating relays are operating.

2. In a telephone exchange system having a plurality of subscriberslines and pulse responsive equipment operable to establish a connectionbetween any two subscribers lines;

a testing device and automatic dialing routiner connectible to any twoof said subscribers lines, compriszng means to create pulses of a properspeed and ratio to operate said pulse responsive equipment for thepurpose of establishing a connection between the said two selectedsubscribers lines;

[The testing device according to claim 1, and having,

in addition to] a generator responsive relay to control the restartingof the pulse transmission a relay operable through the reversal of thecurrent on the tip-ring leads, associated with subscribers line selectedas the calling line, by the pulse responsive equipment, said relaycontrolling the re-starting of the pulse transmission cycle inconjunction with the generator responsive relay {and having];

a manually operated [toggle switch} device to transfer the re-startingcycle from the control of the generator responsive relay alone to thedual control of the generator responsive relay and the said relayoperable by the tip-ring reversal and [having] a lamp to visuallyindicate that the said tipring reversal of current feature is beingtested.

3. In an automatic dialing routiner and grade of service recorder foroperating and testing certain selected telephone equipment incombination,

means comprising a pulse generator for applying pulses to a switch trainof said selected telephone equipment; and

means comprising a plurality of digit switches, a stepping switch, andelectrical connections between said pulse generator, said digitswitches, and said stepping switch for controlling the pulse generatorand for automatically selecting the digits to be dialed;

an alarm bell;

means comprising a contact, and electrical connections between saidcontact and said alarm bell effective when said telephone equipment isbeing operated 21 2-2 to operate said alarm during the period betweenthe said first relay, will be effective to energize said last digits ofthe selected number; relay,

and means comprising a relay controlling said conand said last relayincluding a means, which when tact, effective when there is a stoppageof the operatoperated to an open position by the energization ing of thesaid telephone equipment to operate said 5 of said last relay, willcause said first relay to be dealarrn continuously. energized,

4. In an automatic dialing routiner and grade of service and said lastrelay also including a separate means recorder for operating, testingand recording the operawhich, when operated to a closed position byention of selected telephone equipment having a connector ergizaion ofsaid last relay, will cause the telephone switch and an answer relay insaid connector switch in equipment attached to the routiner to becomeenwhich the telephone equipment is capable of causing a ergized and,which when operated to an open posicurrent reversal from the answerrelay of the connector tion by the de-energization of said last relay,will switch on the calling side of the equipment to be returned causethe telephone equipment attached to the routo the routiner, comprisingin combination, tiner to become de energized, the alternateenergizemeans comprising a pulse generator for applying election of thesaid first and last relays thus causing trical pulses to said selectedtelephone equipment; the telephone equipment to be pulsed;

means [comprising a plurality of digit switches, a stepand separatemeans for holding the last relay energized ping switch magnet, andelectrical connections beduring interdigital timing in order toguarantee that tween said pulse generator, said digit switches, and allpulses of a digit being transmitted to the telesaid stepping switchmagnet] for controlling the pulse phone equipment will be of equallength to the telegenerator and selecting the digits to be dialed inapphone equipment being pulsed. plying said electrial pulses to saidselected telephone equipment; and References Cited in the file of thispatent means, comprising [a relay] equipment in the dialing or theOngmal Patent routiner responsive to receipt of said current reversalUNITED STATES PATENTS by the dialing routiner from the answer relay ofthe 1,632,902 Johnson June 21, 1927 connector switch of the calhng sideof the equipment 1 641 453 Ostline Se t 6 1927 p and electricalconnections connectlng sald relay to the 2 293 611 Meeds Aug 18 1942calling side of the equipment, for releasing the se- 2,585,023 LewisFeb. 12, 1952 lewd equlpmem- 2,680,161 Clement June 1, 1954 5 A pulsecreating generator for an automauc diallng 2,914,624 Murray Nov 24 1959routiner for pulsing selected telephone equipment attached to theroutiner comprising, in combination, OTHER REFERENCES a plurality ofrelays including a first relay and a last The Design of SwitchingCircuits, Keister et al., copyrelay, said first relay including a meanswhich, when right 1951, D. Van Nostrand Co., page 406. operated to aclosed position by energization of the

